The present invention relates generally to an improved electronic imaging printing apparatus for optically printing and developing images on image recording material as such material is advanced along a preselected path in the apparatus.
Various forms of electronic imaging printers which generate and record images representative of electronic information, on image recording material are well known in the art.
One known kind of printer utilizes a cathode ray tube for presenting information in visual form on a screen while image recording material moves therepast so as to capture the visual information. Exemplary of printers of this type is one described in U.S. Pat. No. 4,467,369 commonly assigned herewith. Another known type is described in U.S. Pat. No. 4,179,183, wherein there is disclosed a light beam scanning apparatus for use as an electronic image printer. Included is a polygonal mirror rotated at a constant speed and a lens system which focuses the scanning beam deflected by the polygonal mirror onto an image recording surface to be scanned. There are disadvantages associated with such a system. For instance, the repeatability of the scanning action provided by the mirror is less than entirely reliable due to the precision required to rotate the mirror and the wear associated with such rotation. Both of these factors can lead to unacceptable tilting of the scanned lines. Therefore, the quality of the resultant image especially in photographic quality prints, is less than desired. It will be appreciated that misplacement of even one scanning line can affect adversely the quality of the images produced.
Still another type of electronic image printing apparatus is disclosed in U.S. Pat. No. 4,564,853, commonly assigned herewith. In this patent there is described XY scanning galvanometer/mirrors which addressably line scan a laser beam that is modulated in response to the electronic image data across the surface of the liquid crystal light valve and to thereafter reflect a beam of incoherent light through a liquid crystal light valve to expose photosensitive material through a filter wheel having red, green and blue filters.
Yet still another kind of electronic imaging printer is described in commonly assigned U.S. Pat. No. 4,566,015, wherein there is disclosed an image recording apparatus for recording images on an advancing sheet of photosensitive material by using light emitting diodes in a line exposure array. The diodes are oscillated to displace each diode along a line of exposure.